The present invention relates generally to seat restraint systems for vehicles and, more particularly, to a tension sensing assembly for a seat restraint system in a vehicle.
It is known to provide a seat restraint system such as a seat belt in a vehicle to restrain an occupant in a seat of the vehicle. In some vehicles, the seat restraint system may be a lap belt, a shoulder belt, or both. Typically, the lap belt and shoulder belt are connected together at one end. The seat restraint system includes a latch plate at the connected end. The seat restraint system also includes a buckle connected at one end by webbing or the like to vehicle structure. The buckle receives the latch plate to be buckled together. When the buckle and latch plate are buckled together, the seat restraint system restrains movement of the occupant to help protect the occupant during a collision.
Smart inflatable restraint systems need to know what is occupying a seat of the vehicle. Decisions on deployment of inflatable restraints depend on information supplied by sensors in the seat in determining weight of an object in the seat. When a child seat is placed in the seat and cinched down, the sensors may read a large mass instead of a child seat. With this condition, there will be high tension in the seat restraint system. Comfort studies have shown that no human occupant would wear their seat restraint that tight. With this information on seat restraint tension, the inflatable restraint system can decide on deployment of the inflatable restraints.
Therefore, it is desirable to provide an assembly for sensing tension in a seat restraint system of a vehicle. It is also desirable to provide an assembly for a seat restraint system in a vehicle that allows a control module to determine the difference between either a child seat or a small occupant. It is further desirable to provide an assembly for a seat restraint system in a vehicle that provides an indication of low tension forces while preventing audible noise due to rattle and provide an indication of high tension forces in the seat restraint system.
It is, therefore, one object of the present invention to provide a tension sensing assembly for sensing tension in a seat restraint system of a vehicle.
It is another object of the present invention to provide an assembly for dual level tension sensing in a seat restraint system of a vehicle.
To achieve the foregoing objects, the present invention is a tension sensing assembly for a seat restraint system in a vehicle including a housing for operative connection to vehicle structure and at least one spring disposed in the housing. The tension sensing assembly also includes at least one magnet disposed in the housing and a Hall effect sensor disposed in the housing and cooperable with the at least one magnet. The tension sensing assembly further includes a movable mechanism at least partially disposed in the housing and cooperable with belt webbing of the seat restraint system and the at least one spring to move the at least one magnet relative to the Hall effect sensor to change an output of the Hall effect sensor to indicate a first tension level and a second tension level in the seat restraint system when the at least one spring is deflected.
One advantage of the present invention is that a new tension sensing assembly is provided for a seat restraint system in a vehicle. Another advantage of the present invention is that the tension sensing assembly senses tension in the seat restraint system to help identify what is occupying the seat, either a child, child seat, or low mass adult. Yet another advantage of the present invention is that the tension sensing assembly has dual level tension sensing. Still another advantage of the present invention is that the tension sensing assembly employs dual level spring operation to provide sensing device travel at low tension forces, prevent rattle, and still provide output at higher forces. A further advantage of the present invention is that the tension sensing assembly has greater output at lower tensions and greater control of output. Yet a further advantage of the present invention is that the tension sensing assembly may use ortho-planar or flat springs and reduce assembly forces to ease automated assembly.
Other objects, features, and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.